The present invention relates generally to improved methods and apparatus for cooking foods. More particularly, the present invention relates to control of various operational functions of a cooking device such as, for example, temperature, time, and/or alarm functions. More particularly, the invention pertains to such control using measurement of parameters such as, for example, detecting and measuring at least a portion of the smoke generated by the item(s) being cooked in the oven and/or detecting and measuring the presence of at least a portion of gases generated during the cooking process.
Many household and industrial devices, such as ovens, toasters bread machines and the like are used for cooking food. A problem with conventional devices is that they typically operate by having a user set a cooking temperature and/or cooking time. The user may inadvertently set one of these settings incorrectly for the food being cooked. For example, if the temperature is set too high, and/or the cooking time is set too long, then the food will burn undesirably, which can ruin the food, cause unwanted smoke to build up in the device, and/or present a fire hazard. Also, food burning can begin to occur before any smoke is noticeable to an operator in the vicinity of the cooking device. Further, with the ability of Internet enabled cooking devices that can be remote controlled, it is desirable to enhance the safety of such devices by providing increased monitoring and safety control.
Accordingly, it is desirable to provide a method and apparatus that can control various operational functions of a cooking device such as, for example, temperature, time, and alarm functions, to prevent or reduce burning of the item(s) being cooked.
It is therefore a feature and advantage of the present invention to provide control of at least one operating feature of a cooking device in response to measured smoke and/or gas produced by item(s) being cooked. The above and other features and advantages are achieved through the use of a novel apparatus and method as herein disclosed.
In accordance with one embodiment of the present invention, the invention operates by measuring during cooking a parameter of at least a portion of the smoke generated by the item(s) being cooked, and by controlling an operating feature of the cooking device in response to such measurement. The feature being controlled may be the device temperature, the cooking time, activation of an alarm and/or a fire suppression feature. The preferred controlling assembly of the invention may include a sensing chamber together with a delivery system (e.g., a passageway) communicating the cooking device interior and the sensing chamber in order to convey at least a portion of the smoke evolved during the cooking cycle to the sensing chamber. A smoke detector is associated with the sensing chamber in order to measure the smoke parameter of interest. Advantageously, the smoke detector may be a conventional infrared smoke detector which is coupled with an electronic controller, in order to measure the a parameter of smoke generated during at least a portion of the cooking cycle. Also, an in-line smoke filter may be interposed in the delivery system to remove the largest smoke particles. This reduces the rate of smoke contamination of the sensor chamber and other components.
In another embodiment, the present invention uses a gas sensor operable to measure during cooking a parameter of at least a portion of the gas generated by the item(s) being cooked, and by controlling an operating function of the cooking device in response to such measurement. The cooking device function being controlled may be the temperature, the cooking time, activation of an alarm and/or a fire suppression feature. The gas being measured is preferably CO2, although other gases may be measured. The preferred gas sensor operates under the principle of infrared absorption, which states that a gas will proportionally absorb infrared radiation or other radiant energy having particular characteristics, such as a particular wavelength or range of wavelengths. Thus, by exposing the gas sample to infrared energy having the appropriate characteristics with regard to the gas component of interest, and measuring the amount of unabsorbed radiation, the amount of the particular gas component can be determined as being proportional to the difference between the amount of sourced radiation and the amount of detected radiation. In a preferred form, the detector""s measurement is compared to a predetermined reference value, with the reference value being established under known conditions, such as the absence of the gas of interest.
Preferably, the following parameters may be used in control of the cooking process: oven temperature, level of smoke, levels of CO, CO2, and/or H2O. Different cooking devices may use some or all of these parameters. Temperature may be measured by the oven control. The sensor(s) will be able to measure any one (or any combination) of the rest of the parameters.
The oven control function, that depends on the value of the measured parameters can be generated by either the sensor or the oven controller. Normally the oven controller is a separate unit within the cooking device. It is possible that the sensor and oven controller will be integrated into a single unit. This depends on which implementation provides lower overall cooking device cost.
Although some embodiments use IR gas sensing devices, the particular gas sensing method can be selected based on various factors such as a cost/performance combination. In some embodiments, IR-absorption gas sensing devices are preferred because of their reliability and long life time.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.